It Came from the Third Dimension
Apr 9, 2009 12:00 PM, By Michael Goldman
DreamWorks rethinks 3D production with Monsters vs. Aliens.
One of the earliest moves the production made was to accept an invitation from Cameron to visit the Avatar virtual set and research that project's advances in terms of virtual stereoscopic cinematography.
"We had a lot of sharing back and forth with Cameron's group at that time since we were all trying to get 3D going at about the same time," Letterman says. "I distinctly remember asking Cameron how he deals with what I felt were very tricky constraints imposed on the filmmaker by 3D, and he basically said, â€˜Don't worry about that stuff. Just shoot your movie.' From that moment on, it was a big relief for me—we allowed it to become a natural process for us. We had an action movie, and rather than altering that, we asked, for instance, for tools to allow that kind of pace."
McNally says that the production's interaction with Cameron's team was particularly helpful.
"The main thing we took away was [how to do] virtual camera work on a CG set," McNally says. "Not just the stereoscopic nature of it, but the idea that we have a piece of technology that looks like a small TV with handles on it. And when you look at the TV, what you are really seeing is the virtual CG set [as you walk around the set]. As we move it around, the motion is recorded as animation curves in the computer. To be able to wander around the set as if you were holding a camera is something that Damon O'Beirne, our [head of layout], was very excited about—the idea you could reshoot your animation with a handheld, live feel. This was especially fortunate for some of our action sequences where you want to feel you are under pressure with things exploding and ripping apart. It's also allowed him to do very subtle adjustments—the kind of things that only happen when there is someone operating a camera. It's pretty easy in CG to make camera moves smooth and almost ahead of action, predicting where things would move, because we can dial it in so perfectly. Adding a little bit of imperfection is a good way to get past that. So we set up our own camera capture system at DreamWorks after seeing the benefit of it on the Avatar set. It's really a way to look at your virtual environment in the computer if you are standing and moving through it. The main benefit is the natural feel of the camera that it gives us."
Among the action sequences McNally references is the movie's centerpiece action moment: a battle between monsters and aliens in downtown San Francisco and on the Golden Gate Bridge. In terms of both visualizing the sequence and cutting it, filmmakers insist the scene achieves their pacing goals without bowing to the traditional confines of 3D, but with all of the medium's advantages.
Letterman says the scene is the one he is most proud of in the movie and suggests that it has a visual depth and style that would not normally be found in a standard CG presentation.
"[The scene] is meant to have the feel of live action, and that means it can't be too perfect [with camera movement] as most animated movies tend to be," Letterman says. "They also tend to be too linear. Our approach with this scene was to break that up and do something totally different, including the way the camera moves through space. There was specific intent to move straight down the Z axis, not moving across the screen as much as moving behind the screen. We put in handheld shots and quick cuts and racing along the bridge, and we also shot coverage, which is uncommon in animation. In this sense, 3D really stood out because we could go down deeper and then come back instead of just pushing out at the [viewer's] face. There was a sense of volume to it—moving through very big spaces. We tried to make you feel the volume, and those are choices we probably would not have made in 2D."
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